Allow constants names to start with digits

[jubianchi]

$ echo -n '2_OVER_314*2' | vendor/bin/hoa compiler:pp Arithmetic.pp 0 -s

 #  namespace     token name            token value                     offset
-------------------------------------------------------------------------------
 0  default       constant              2_OVER_314                           0
 1  default       times                 *                                   10
 2  default       number                2                                   11
 3  default       EOF                                                       12

[Hywan]

👍

[Hywan]

You can move the number token after the constant token to avoid 7A to be consumed as a number 7 and a constant A instead of the constant 7A.

[Hywan]

And this way you might remove \b.

[jubianchi]

i was wondering what the best solution was ;) I'll move the lines if you prefer :)

[Hywan]

It's better to move the line I guess.

[jubianchi]

@Hywan & @hoaproject/hoackers good for me, let me know if I have to change anything else.

[Metalaka]

Good for me if you have thought about this:

Constants starting with digits can looks like hexadecimal value, so 0X1A is it a constant or the decimal value 26 ?

With this grammar it's a constant since we don't recognize (yet?) hexa/binary values.

http://php.net/manual/en/language.types.integer.php
hexadecimal : 0[xX][0-9a-fA-F]+

[jubianchi]

@Metalaka fair point!

The question is do we plan to support hex. values ? (@Hywan)

If yes, we'll have to find a consistent way to handle them among constants and ids.

[jubianchi]

Here is what I can propose:

• \x1A for hex values,
• \0755 for octal values,
• \b010101 for binary values

I already patched the grammar and the arithmetic visitor:

diff --git c/Arithmetic.pp i/Arithmetic.pp
index 02cc0fe..b948e11 100644
--- c/Arithmetic.pp
+++ i/Arithmetic.pp
@@ -44,13 +44,16 @@
 %token  bracket_  \(
 %token _bracket   \)
 %token  comma     ,
+%token  hex       \\x[0-9a-fA-F]+
+%token  octal     \\0[0-7]+
+%token  binary    \\b[01]+
 %token  constant  [0-9_]*[A-Z_]+[A-Z0-9_]*
+%token  id        \w+
 %token  number    (0|[1-9]\d*)(\.\d+)?([eE][\+\-]?\d+)?
 %token  plus      \+
 %token  minus     \-|−
 %token  times     \*|×
 %token  div       /|÷
-%token  id        \w+

 expression:
     primary() ( ::plus:: #addition expression() )?
@@ -73,7 +76,10 @@ term:
   | function()

 number:
-    <number>
+      <number>
+    | <hex>
+    | <octal>
+    | <binary>

 constant:
     <constant>
diff --git c/Visitor/Arithmetic.php i/Visitor/Arithmetic.php
index a7da754..32d808f 100644
--- c/Visitor/Arithmetic.php
+++ i/Visitor/Arithmetic.php
@@ -255,6 +255,12 @@ class Arithmetic implements Visitor\Visit
                     }
                 } elseif ('id' === $element->getValueToken()) {
                     return $value;
+                } elseif ('binary' === $element->getValueToken()) {
+                    return bindec($value);
+                } elseif ('hex' === $element->getValueToken()) {
+                    return hexdec($value);
+                } elseif ('octal' === $element->getValueToken()) {
+                    return octdec($value);
                 } else {
                     $out = (float) $value;
                 }

I ran this through those tests:

echo -n '2_SQRT_314 * 2' | vendor/bin/hoa compiler:pp Arithmetic.pp 0 -s
echo -n '2xfoo * 2' | vendor/bin/hoa compiler:pp Arithmetic.pp 0 -s
echo -n '0XA * 2' | vendor/bin/hoa compiler:pp Arithmetic.pp 0 -s

echo -n '\x1A * 2' | vendor/bin/hoa compiler:pp Arithmetic.pp 0 -s
echo -n '\0755 * 2' | vendor/bin/hoa compiler:pp Arithmetic.pp 0 -s
echo -n '\b01001 * 2' | vendor/bin/hoa compiler:pp Arithmetic.pp 0 -s

echo -n '\b01001' | vendor/bin/hoa compiler:pp Arithmetic.pp 0 -c Hoa.Math.Visitor.Arithmetic -s
echo -n '\x1A' | vendor/bin/hoa compiler:pp Arithmetic.pp 0 -c Hoa.Math.Visitor.Arithmetic -s
echo -n '\0755' | vendor/bin/hoa compiler:pp Arithmetic.pp 0 -c Hoa.Math.Visitor.Arithmetic -s

P.S: I could easily open a third PR for this feature if we want this ;)

[jubianchi]

Could not resist opening the PR: #40 ;)

[Hywan]

Hehe, I am sorry but… this is a Maths library. Did you ever write an hexidecimal value in a Math equation :-p? Personally, no. Thoughts?

[jubianchi]

@Hywan maths are not only decimal. One may need to do binary computations and get a decimal result.

[Savageman]

I agreee with @jubianchi : Math is just a tool. Mathematicians will use the most appropriate paradigm to solve their problems, and decimal is not always the best tool to solve a problem.

As for syntax, PHP uses natively 0660 for octal, 0x1A for hexa and 0b01001 for binary. Since it's a PHP library it would make sense to use the same?

[Hywan]

So a number must be start by 0 and the problem will be solved. It sounds correct too, a lot of language does this.

[jubianchi]

let's close this one! (#41 (comment))